Thermodynamic Evaluation for the Y2O3–BaO–CuOx System |
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Authors: | Byeong-Joo Lee Dong Nyung Lee |
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Affiliation: | Department of Metallurgical Engineering and Center for Advanced Materials Research, Seoul National University, Seoul 151-742, Republic of Korea |
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Abstract: | The thermodynamic data for the Y2O3–BaO–Cu2O–CuO quaternary system were optimized from measured thermodynamic data. A two-sublattice model for ionic solution was used to express the Gibbs free energy of the liquid phase, and a two-sublattice regular solution model was used for the nonstoichiometric YBa2Cu3O6+δ superconducting compound. The optimized thermodynamic data were used to calculate the phase diagrams of the Cu2O–CuO binary system and the CuO x –Y2Cu2O5 and CuO x –BaCuO2 quasi-binary systems. The results were in good agreement with reported measured data. The liquidus projection and isothermal and vertical sections of the Y2O3–BaO-CuO x quasi-ternary system were calculated. The effect of oxygen pressure on some reaction temperatures was predicted by calculating them at various oxygen pressures, and the oxygen contents (6 +δ) in YBa2Cu3O6+δ were calculated at various temperatures and oxygen pressures. The results were compared with experimental data. |
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Keywords: | superconductors models thermodynamics phase equilibria oxygen partial pressure |
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